NOL5A is similar in sequence to Nop56p, a yeast nucleolar protein that is part of a complex with the nucleolar proteins Nop58p and fibrillarin. Like Nop56p, NOL5A is found in the nucleolus and is though to be required for 60S ribosomal subunit biogenesis. Multiple transcript variants encoding several isoforms have been identified for this gene, but the full-length nature of most of them is not yet determined.